Tube bending apparatus



May 4, 1965 K. BOS 3,181,323

TUBE BENDING APPARATUS Filed Nov. 21, 1961 11 Sheets-Sheet 1 In venlor B, MMfi Attorney TUBE BENDING APPARATUS Filed NOV. 21, 1961 ll Sheets-Sheet 2 In venlor 414/ Atlorne y Filed Nov. 21, 1961 11 Sheets-Sheet 3 I nvenlor By MM fl M Attorney May 4, 1965 K. Bos

TUBE BENDING APPARATUS 11 Sheets-Sheet 4 Filed NOV. 21 1961 VVVVV S d/MM 2! Attorney K. BOS

TUBE BENDING APPARATUS May 4, 1965 ll Sheets-Sheet 5 Filed NOV. 21, 1961 W Inventor ByW/MW 64/ Attorney May 4, 1965 K. 505 3,181,323

TUBE BENDING APPARATUS Filed Nov. 21, 1961 11 Sheets-Sheet 6 0 & no g I g I Q 5% Q i l a Q: W444 Inventor WMfi-Z MM Attorney May 4,1965 K. B05 3,181,323

TUBE BENDING APPARATUS Filed Nov. 21. 1961 11 Sheets-Sheet 7 In oenlor By 10M MM Allorne y May 4, 1965 K. BOS

TUBE BENDING APPARATUS 11 Sheets-Sheet 8 Filed Nov. 21, 1961 lnvenlor By MM Attorney May 4, K. BOS TUBE BENDING APPARATUS Filed Nov. 21, 1961 11 Sheets-Sheet 9 Inventor B WWW @[M Attorney May 4, 1965 K. 508

TUBE BENDING APPARATUS 11 Sheets-Sheet 10 Filed NOV. 21. 1961 www I nvenlor By Attorney May 4, 1965 B05 3,181,323

TUBE BENDING APPARATUS Filed Nov. 21, 1961 11 Sheets-Sheet 11 KM fl Inventor B WW M Attorney United States Patent 3,181,323 TURF. EENDING APPARATUS Karel Iios, 1151i Pierneef Sh, Pretoria, Transvaal, Republic of South Africa Filed Nov. 21, 1961, Ser. No. 153,814- Claims priority, application Republic of South Africa, Nov. 28, 1960, 4,821/69 Uiaims. (Cl. 7226) This invention relates to apparatus suitable for bending work pieces such as rods or tubes or uniform cross sectional dimensions about their axes and also along their lengths, to varying degrees of bend in various planes spaced axially along the length of the work piece. The invention relates more particularly to tube bending apparatus suitable for the bending of tubes for the exhaust systems of motor vehicles.

It is an object of this invention to provide a versatile machine for the bending of motor vehicle exhaust tubes and which can be quickly and easily set for the bending of various batches of tubes having varying characteristics regarding the position, spacing and disposition of bends relative to each other.

According to the invention, bending apparatus suitable for the bending of work pieces of the kind referred to, includes bend parts comprising a bend former and at least one co-acting part to clamp a work piece for bending transverse to an alignment axis, actuating means for displacing at least one of the bend parts to bend the work piece, and locating means for locating a work piece c0- axially with and relative to an alignment axis by locating one end of the work piece both in axial distance from the bend former and in its rotational disposition about the alignment axis; the locating means comprising a shaft disposed longitudinally and having its axis parallel to the alignment axis, axially spaced transversely disposed arms fast with and circumferentially spaced about the axis of the shaft, the axial spacing between the various arms corresponding to the various pitches between bends to be formed in a work piece, and engaging means on each transverse arm and mounted to be adjustable in position in the arm about an axis parallel to the shaft axis, for locating the rotational position of a work piece about the alignment axis to determine the angle between the planes of the bends to be formed in the work piece.

At least one of the bend parts may be mounted to rotate about an axis at right angles to the alignment axis. The locating means may comprise at least one rail disposed longitudinally parallel to the alignment axis; a carriage linearly displaceable along the rail, a chuck mounted to rotate about the alignment axis in bearings fast with the carriage, the chuck having a bore and being adapted to receive a work piece within the bore and to grip and locate it coaxially with the alignment axis; mating means mounted to rotate in bearings fast with the carriage about an axis parallel to the alignment axis and adapted to engage coaxially with the engaging means of the transverse arms for locating the carriage longitudinally relative to the bend former; a toothed wheel fast with the mating means; a toothed wheel fast with the chuck; and drive means connecting the toothed wheels to ensure positive positioning of the chuck and work piece about the alignment axis in correspondence with the disposition of the mating means about its rotational axis; whereby a Work piece may be gripped in the chuck, the longitudinal position of the carriage relative to the bend former located by the longitudinal position of an arm brought into alignment with the mating means axis, and the rotational disposition of the chuck and a gripped work piece about the alignment axis located by engaging means via the mating means and chuck toothed wheels and drive means, and the work piece bent by displacing one of the bend parts the required amount about the rotational axis at right angles to the alignment axis, the carriage being free to move with the work piece towards the former as bending proceeds.

A work piece may be in the form of a tube, and may comprise a mandrel and means to retain it in alignment with the alignment axis and close to the bend former, the mandrel being receivable longitudinally within a work piece being bent. The axis of the engaging means of each arm registers with the alignment axis upon rotation of the shaft, and the bend former may be a bend block of segmental shape displaceable at right angles to the alignment axis, and the coacting part may comprise a pair of biassed wing dies mounted to rotate about a pair of longitudinally spaced transverse axes, one on either side of the bend block, the bias being arranged to urge the wing dies towards the bend block; whereby a work piece may be gripped in alignment with the alignment axis and the bend block displaced by the actuating means in a direction at right angles to the alignment axis an amount corresponding to the degree of bend required.

Further features of the invention will become apparent from the following description of a specific embodiment and modification with reference to the accompanying drawings, the description being given by way of example only.

In the drawings:

FIGURE 1 shows a front elevation of the head end of a bending machine in accordance with the invention;

FIGURE 2 shows a front elevation of the tail end of the machine shown in FIGURE 1;

FIGURE 3 shows a front elevation of an arm;

FIGURE 4 shows a part plan view of the adjustment between plug and arm;

FIGURE 5 shows a part sectional detail side elevation of a tube tail end and plug;

FIGURE 6 shows a side elevation of the head end of a machine similar to that shown in FIGURE 1;

FIGURE 7 shows a detail of the pressure head and part of the machine indexing mechanism;

FIGURE 7a shows a detail end view of the cam assembly shown in FIGURE 7;

FIGURE 8 shows a rear elevation of the tail end of the machine;

FIGURE 9 shows a plan view corresponding to FIG- URE 8; 1

FIGURE 10 shows an end elevation corresponding to FIGURES 8 and 9;

FIGURE 11 shows the circuit diagram of the energising circuit for the shaft drive means and ancillary gear;

FIGURE 12 shows the circuit diagram of the actuating means;

FIGURE 13 shows diagrammatically the combination of locating means according to the invention in combination with a mandrel bending machine;

FIGURE 14 shows a front elevation of a carriage of the combination shown in FIGURE 15; and

FIGURE 15 shows a part sectional end elevation at XIV-XW of the carriage shown in FIGURE 14.

The invention comprises broadly two types of apparatus, namely the first type in which the machine comprises a combination of locating means with a bend former transversely displaceable to the alignment axis to bend a work piece, and secondly, by way of modification, the combination of the locating means with a conventional mandrel type bending machine, but which can also be used for the bending of solid work pieces. The first mentioned type of machine will first be considered in broad terms, and its operation described, and then the apparatus will be described in greater detail with reference to the various parts and to their method of operation. Thereafter the modification of the invention comprising the mandrel type, will be described.

Reference numeral shows the machine having bend parts 12 comprising a bend former 14 and wing dies 16. The bend former 14 is provided at the lower end of a pressure head 13, which is vertically displaceable transversely to the alignment axis 15 by actuating means 304. Bias means in the f0rm.of weight 18 suspended from pulleys 19 by means of steel wire ropes 20 deflected around running sheave 21 and deflecting pulleys 22 are adapted to restrain the arcuate displacement of wing dies 16 in the direction of arrows 24 when pressed by Work piece 26 under the action of bend former 14, when displaced transversely to alignment axis 15. The weight 18 is guided .for linear up and down movement in the direction of arrow 300, by guide posts 302 supporting actuating means .364 in an elevated position. (See FIGS. 1 and 6). The running sheave 21 acts to equalise loads on the wing dies 16. The trailing end 28 (see FIGURE 5) of a work piece in the form of a tube 26 having a notch 30 is adapted to receive engaging means in the form of plug 34 and. projection or key 32. Locating means generally referred to by 33 comprises an arm 36 fast with shaft 38 having its axis parallel to'the work piece axis which iscoincident with the alignment axis 15, when the tube is clamped and immediately before bending starts.

The locating means comprises also further arms 36 on the shaft 38, at varying longitudinal positions from bend former 14 and at varying arcuate dispositions about the axis of shaft 38. The plug 34, in turn is fast with a calibrateddisc 41). (see FIGURE 4) mounted in a seat in arm 36, the seat having a datum point 42. The disc may be set at any position about its axis, and locked in that position. The disposition of the various arms 36 about the shaft axis may be determined by the position of the keyway 44 in the bore of the arm 36 adapted to receive the shaft 38. The' shaft 38 has one long key-way 46 within which graduations are provided for easy longitudinal positioning. of the arms 36 on the shaft 38. The graduations 45 have the vertical centre line of the bend former 14 as their datum line. The shaft 38 at its leading end is supported in a bearing 48 on a column 50 (see FIGURE 1) and at its tail end in a bearing in tail end box 52 (see FIGURE 2) housing indexing means 117.

. The shaft 38 is mounted tobe longitudinally displaceable in direction of arrow 100 and to rotate about its axis in its bearings 48. Means 137 to rotate it is disposed within the tail end box 52 and will be more fully described hereafter. The longitudinal positioning of the tail end box 52 relative to the head end of the press is adjustable for final positioning by means of tie rod 54. A micro head switch 53 (see FIGURE 7) is provided between spindle 56 and frame part 58 (see FIGURE 1) to close as soon as predetermined slack allowed between them has been taken up. In coming together the former 14 and the wing dies 16 are in position merely to grip the tube firmly. When the head switch 53 operates, it energises a solenoid in the tail end box 52 which operates an air valve (not shown) to admit compressed air into a cylinder 92 to displace a piston 31 to displace the shaft 38 axially via lever system 61 to withdraw a plug 34 from engagement with the tail end 28 of the tube 26. (See FIGS. 8, 9, 10).

Thereupon displacement of former 14 by the press continues and bends the work piece. Bending of the work piece causes the wing dies 16to be displaced arcuately, and a limit micro switch 63 fast with shoe 78 (see FIGURE 7) to rise in correspondence with the amount of bending required until it abuts against a stop 62 (see FIGURES l and 7) to stop and to reverse the press by stopping and reversing the actuating means 304. It will be noted that there are a number of stops 62, each corresponding to one of the arms 36 on the shaft 38. The vertical adjustment of the stops 62 on spider 64 determines the amount of the bend, the radius of the bend being determined by the shape of the former 14 and wing dies 16.

In operation, in the bending of a Work piece in the form of a tube, the tail end 28 of the tube to be bent is engaged with an arm 36 suitably positioned axially on the shaft 38 and about the shaft axis, to correspond to the leading bend to be made in the tube. As soon as the tube has been clamped the head switch 53 closes and the plug 34 in engagement with the tail end of the tube withdraws in the manner previously described. Thereupon the former 14 is fully displaced until the limit micro switch 63 abuts against the stop 62 in line with it and corresponding to the bend. This determines the degree of the bend. In bending, the tail end 28 of the tube 26 rises, and the wing dies 16 are arcuately displaced about their pivotal axes, i.e. the axes of shafts 70 (see FIGURE 7). Longitudinal anchor bars 310 providing anchoring for flexible elements 20, are fast with the wing dies 16 and are arcuately displaceable with them in direction of arrows 312. Support posts 314 limit the downward displacement of the anchor bars 310. (See FIG. 1.)

The limit micro switch 63 also triggers a circuit to energise motor 138 to cause the shaft 38 to rotate about its axis a determined amount to bring another arm 36 which is nearer to the former 14, so that its plug 34 is coaxial with the alignment and tube axis. At the same time the spider 64 is rotated about its axis via chain drive 150, flexible cable 66, and shaft 68 to bring the stop 62, corresponding to the arm now in position, into line with the limit micro switch 63. The tube is advanced longitudinally and its tail end engaged with the plug and key new in position. This plug now determines the longitudinal position of the bend and the key determines the plane of the bend relative to the first bend. After each bend has been completed the end of the work piece is engaged by the operator with the plug 34 of the arm 36 which has been newly indexed and execution of the bend corresponding to that arm, and its stop 62 takes place. In this Way successive bends axially spaced, in different planes and of different degrees can be quickly carried out.

Similar bends, trailing the others are similarly carried out, characteristics of each succeeding bend being determined by the position and disposition of a plug 34 and an arm 36 closer than the plug and arm of the preceding bend.

The apparatus and its method of operation having now been broadly described, the various subsidiary parts of the apparatus will now be described in greater detail, and their function described.

Referring to FIGURE 7 of the drawings, there is shown a detail of part of the machine head, with bend former 14 and wing dies 16. Fast with wing dies 16 there are provided shafts 79, for supporting the wing dies arcuately about their axes. Fast with one of the shafts 7%, there is provided a cam 72 having a cam face 74. There is further provided a steel tape 76, adapted to ride on cam face 74, and having its upper end fast with cam face 74. The lower end of tape 76 is fast with shoe 78 which is guided for linear upward displacement by guides 8G and which is biased downwardly by its own weight. Fast with shoe 7 8 there is provided limit micro switch 63.

As will be noted, the spider 64 is mounted to rotate about an upright axis close to the limit micro switch 63, such that stops 62 attached to the spider 64 can come discretely into register with limit micro switch 63. During the bending process the bend former 14 is displaced downwardly in the direction of arrow 82, wing dies 16 are displaced arcuately against bias weight 18 about the axes of shafts 70 in the direction of arrows 24, and cam 72 is displaced arcuately in the direction of arrow 84. Such arcuate displacement of the cam 72 about axis of shaft 70, causes the upward displacement of shoe 78 in the direction of arrow 8:5.

Referring now to FIGURES 8, 9, and 10 of the drawings, the parts comprising the tail end box 52, and their operation will now be described. To enable the tube to be bent after the slack has been taken up and the tube has been firmly gripped between bend former 14 and wing dies 16, it is necessary that the arm 36 be axially displaced, to withdraw plug 34- and key 32 from the end 28 of the tube 26, before actual bending of the tube starts. This is achieved by the operation of head switch 53 which closes the energising circuit for the coil 91 (see FIGURE 11) of a solenoid to operate an air valve not shown, to admit air into a cylinder 92 (see FIGURE 8) to cause displacement of lever 94 in the direction of arrow 96, about the axis of pin 98, thus pulling the shaft 38 axially in direction of arrow 100, via links 1112. This causes the plug 34 and key 32 to be withdrawn from the end 28 of the tube 26, and permits the free end of the tube to be freely displaced during the bending process.

Displacement of lever 94 about the axis of pin 98, causes also downwardly arcuate displacement of arm 164 about axis of pin 98. Arm 104 abuts against lever 1116 mounted pivotally in frame members 103 about the axis of shaft 110. Fast with shaft 110 there is provided an arm 112 (see FIGURE carrying dog 114 and biased upwardly by means of compression spring 116.

Fast with the end of shaft 38 there is provided an index plate 118 having a plurality of notches 120 spaced circumferentially around it. Each of these notches 120, corresponds with an arm 36 on shaft 38. The dog 114 is adapted to engage discretely with the notches 124 There is further provided a biased catch 122 fast with bell crank lever 124 mounted pivotally about axis of pins 126, and carrying roller 128. The index plate 118 has a plurality of circumferentially spaced holes 130, adapted to receive inwardly projecting fingers 132 to provide shoulders and adapted to abut against roller 128, when index plate 118 rotates about the axis of shaft 38, thereby releasing catch 122. Hence arm 112 is urged upwardly by compression spring 116, thus urging dog 114 towards engagement with the notch corresponding to the shoulder in the form of finger 132, and corresponding to the arm 36 whose engaging means is to be brought into alignment with the alignment axis.

Arcuate displacement of the arm 112 about the axis of shaft 111), to compress compression spring 116, and to cause withdrawal of dog 114 from a notch 121), causes the closure of index switch 134, to lock the circuit of shaft drive means 137 whereby the shaft 3% is driven in direction of arrow 1% about the shaft axis when head switch 53 closes upon completion of the stroke of head 13. The

arm 112 is retained in its disengaged position, by the biassed catch 122 abutting behind shoulder 115 fast with arm 112. Upon rotation of the index plate 113, in the direction of arrow 136, the next index finger 132, corresponding to the next bend to be bent, abuts against roller 128 to displace lever 124 and to release catch 122. Arm 112 is immediately urged towards the position of engagement of dog 114- with a notch 120 corresponding to its finger 132 and its arm 36. As soon as the notch 121 corresponding to the shoulder or finger 132 which released the catch 122, comes fully into register with the dog 114, then the dog 11 i slips into engagement with that notch, In doing so, index switch 134 is opened, and the shaft drive means 137 comprising motor 138, gear box 1411 and belt drive 142, is deenergised. The belt 142 drives pulley 144 fast with shaft 31 The engagement of the dog 114 with a notch 12%) brings the disc 118 and shaft 38 abruptly to a stop and the tension of the belt 142 is adjusted to permit slippage on pulley 144, by means of a tensioning device generally designated by reference numeral 146 and operable by screw handle 148. Drive from drive pulley 144 to shaft 38 takes place via a square ended shaft 152 and mating socket member 154.

The indexing of shaft 38 is carried over to spider 64 via chain 150 meshing with sprockets fast with shafts 38 and 68, so that a stop 62 corresponding to the arm 36 may be indexed by bringing it into alignment with the limit switch 63. Spider 64 is in the form of an axially loose sleeve over an upstanding spindle 351B fast with flexible cable drive 66. Axial adjustment of spider 64 takes place easily by means of adjustment screw 352 and lock not 354, whereby the elevation of spider 64 may be adjusted in relation to the end of spindle 350, so to provide more or less bending to allow for spring-back depending upon the grade of material used and upon the section of the material. The weight of the spider is sufficient to operate micro switch 63. If for any reason shoe 73 should overrun its path then spider 64 is merely lifted axially ofi spindle 350 without damage. (See FIGURE 7).

Referring to FIGURE 11, there is shown the circuit diagram for the indexing mechanism and for the control of the shaft drive means 137. There is shown a two-way switch 160, for the selection of head switch 53, for the automatic operation and indexing of the apparatus, or for the selection of manually or pedal operable switch 162, for the control of indexing by the operator. There is further shown a coil 164, being the coil of an air break contactor 166, controlling the supply of power to the electric motor 138 of the shaft drive means.

Referring to FIGURE 12 of the drawings, there is shown the circuit diagram, of the actuating means comprising the contactor 171) for a 5 horsepower motor for the workin' stroke, and 172, being the contactor of a 3 horsepower motor for the return stroke. There is shown also the coil 174 of an electro-magnetic brake to stop the head 13 quickly at the completion of the reverse stroke. The 3-phase power supply is indicated by the numbers 1, 2, (p3, attached to the lines. Reference numeral 171 refers to a control switch by means of which contactor may be energized for a working stroke and which maintains itself in circuit via limit switch 63. As soon as the limit of the working stroke is reached then switch 63 operates and opens the holding circuit for contactor 170 which becomes de-energized and closes the circult to operate contactor 172 for reverse motor. This confactor 172 also maintains itself in circuit until its holding circuit is broken at the end of the return stroke by operation of head switch 53. There is also provided a safety switch 173 which is ready to the operator for quickly stopping the machine in case of emergency, by de-energizing all motors.

Referring again to FIGURE 7 of the drawings, displacement up and down of head 13 is achieved by driving spindle 56 about its axis. Predetermined slack of 1 /2 mm. is provided between thrust races 359 and 352 on either side of frame part 58 which is fast with frame part 59 to which is attached head switch 53. Adjustment in the slack is obtained by means of nuts 364 and 366 cooperating with thread 363. The slack is provided in the direction of arrow 370.

Referring now to FIGURE 13 showing the other embodiment of the invention, there is shown a bend former 14a mounted to rotate about axis 2% at right angles to the alignment axis 15. The co-acting part 16a is adapted to operate with the rotatable former 14a. An abutment shoe 16b is provided for restraining swing displacement of the work piece tail end about the axis 2%. Parallel to the alignment axis 15, there is provided a guide rail 202 adapted to guide a carriage 21M linearly along the guide rail, in direction of arrow 2116. The carriage 2114 is provided with guide wheels or shoes 203 for co-operating with the guide rail 2112. Fast with the carriage there is provided a collet chuck 211) having a bore adapted to receive a work piece 26 in the form of a tube. It is possible, however, for this embodiment also to receive a solid bar. The collet chuck are, is mounted to rotate about hearings in the carriage 234, about an axis co-axial with the alignment axis 15. Fast with the chuck 210 there is provided a toothed sprocket 212 engaged by drive chain 214 meshing with sprocket wheel 215 fast with shaft 218 and mounted to rotate about the 7 axis of shaft 218 which is parallel with the alignment axis 15, in arm 220 fast with the carriage 204. There is furthermore provided fast with the shaft 218, mating means 222 adapted to be engaged by engaging means similar to that previously described, and fast with arms 36 mounted on shaft 38. The arms 36 are spaced longitudinally along the shaft 38, and have engaging means in the form of plugs 34 and keys 32, as previously described.

Referring now to FIGURES 14 and 15, the collet chuck 210, has an operating handle 230 whereby the work piece in the form of a tube or of a solid bar may be gripped. The jockey pulley 232, shown in FIGURE 15 is provided to ensure that an adequate tension is maintained in chain 214.

In operation a work piece in the form of a bar 26a, (see FIGURES 14 and 15) is gripped and the carriage is then positioned so that the mating means 222 is in engagement with the engaging means 34, to locate the carriage axially. The angular disposition of the work piece a about the alignment axis, is determined by the angular position of the key 32 about the axis of sprocket 216. The sprocket 21-6 is rotated about its axis, until notch 242 in socket part 244), is in register with key 32 of plug 34. Thereupon the carriage is moved towards the former 14a, and the mating means 222 again brought into engagement with the engaging means of the next arm 36, defining the bend characteristics to be made in the work piece. The carriage 204 is displaceable in the direction of arrow 250 as bend proceeds.

If desired a mandrel 252 may be provided inside a tubular work piece, supported co-axially with the alignment axis. (See FIGURE 13).

Bends of different characteristics may be provided in a work piece by setting arms 36 at appropriate spacings, setting plugs 34 suitably in the arms 36, and providing shoulders 11 32 in index plate 118 at suitable positions corresponding to the arms 36 and to the bends required. The machine can therefore be quickly and easily set up for the mass production of dilferent batches of tubes, one batch having characteristics different from another.

By way of explanation, the displacing means 92 acts also as bias means depending upon the side of the plunger 91 to which compressed air is admitted.

I claim:

1. In bending apparatus suitable for the bending of workpieces of the kind referred to and which includes bend parts comprising a bend former and at least one coacting part to clamp a workpiece for bending transverse to an alignment axis, and actuating means for displacing at least one of the bend parts to bend the workpiece: locating means for locating a workpiece coaxially with and relative to the alignment axis by locating one end of the workpiece both in axial distance from the bend former and in its rotational disposition about the alignment axis, and comprising a shaft disposed longitudinally and having its axis parallel to the alignment axis; axially spaced transversely disposed arms fast with and circumferentially spaced about the axis of the shaft, the axial spacing between the various arms corresponding to the various pitches between bends to be formed in the workpiece; and engaging means on each transverse arm and mounted to be adjustable in position in the arm about an axis parallel to the shaft axis, for the polar location of a workpiece about the alignment axis to determine the angle between the planes of the bends to be formed in the workpiece.

2. In bending apparatus suitable for the bending of workpieces of the kind referred to and which includes bend parts comprising a bend former and at least one coacting clamp part to clamp a workpiece for bending transverse to an alignment axis the bend former being mounted to rotate about an axis at right angles to the alignment axis: locating means for locating a workpiece coaxially with and relative to the alignment axis by locating one end of the workpiece both in axial distance from the bend former and in its rotational disposition about the alignment axis,

and comprising a shaft disposed longitudinally and having its axis parallel to the alignment axis; axially spaced transversely disposed arms fast with and circumferentially spaced about the axis of the shaft, the axial spacing between the various arms corresponding to the various pitches between bends to be formed in a workpiece; engaging means on each transverse arm and mounted to be adjustable in position in the arm about an axis parallel to the shaft axis, for the polar location of a workpiece about the alignment axis to determine the angle between the planes of the bends to be formed in the workpiece; at least one rail disposed longitudinally parallel to the alignment axis; a carriage linearly displaceable along the rail; a chuck mounted to rotate about the alignment axis in bearings fast with the carriage, the chuck having a bore and being adapted to receive a workpiece within the bore and to grip and locate it coaxially with the alignment axis; mating means mounted to rotate in bearings fast with the carriage about an axis parallel to the alignment axis and adapted to engage coaxially with the engaging means of the transverse arms for locating the carriage longitudinally relative to the bend former; a toothed wheel fast with the mating means; a toothed wheel fast with the chuck; and drive means connecting the toothed wheels to ensure positive positioning of the chuck and workpiece about the alignment axis in correspondence with the disposition of the mating means about its rotational axis; whereby a workpiece may be gripped in the chuck, the longitudinal position of the carriage relative to the bend former located by the longitudinal position of an arm brought into alignment with the mating means axis, and the rotational disposition of the chuck and a gripped workpiece about the alignment axis located by the engaging means via the mating means and chuck toothed wheels and drive means, and the workpiece bent by displacing the bend former the required amount about its rotational axis, the carriage being free to move with the workpiece towards the former as bending proceeds.

3. In bending apparatus suitable for the bending of tubular workpieces and which includes bend parts comprising a bend former and at least one coacting part to clamp a workpiece for bending transverse to an alignment axis, the bend former being mounted to rotate about an axis at right angles to the alignment axis: locating means for locating workpiece coaxially with and relative to the alignment axis by locating one end of the workpiece both in axial distance from the bend former and in its rotational disposition about the alignment axis, and comprising a shaft disposed longitudinally and having its axis parallel to the alignment axis; axially spaced transversely disposed arms fast with and circumferentially spaced about the axis of the shaft, the axial spacing between the various arms corresponding to the various pitches between bends to be formed in the workpiece; engaging means on each transverse arm and mounted to be adjustable in position in the arm about an axis parallel to the shaft axis, for the polar location of a workpiece about the alignment axis to determine the angle between the planes of the bends to be formed in the workpiece; at least one rail disposed longitudinally parallel to the alignment axis; a carriage linearly displaceable along the rail; a chuck mounted to rotate about the alignment axis in bearings fast with the carriage, the chuck having a bore and being adapted to receive a workpiece Within the bore and to grip and locate it co-axially with the alignment axis; mating means mounted to rotate in bearings fast with the carriage about an axis parallel to the alignment axis and adapted to engage co-axially with the engaging means of the transverse arms for locating the carriage longitudinally relative to the bend former; a toothed wheel fast with the mating means; a toothed wheel fast with the chuck; drive means connecting the toothed wheels to ensure positive positioning of the chuck and workpiece about the alignment axis in correspondence with the disposition of the mating means about its rotational axis; and a mandrel and means to retain it in alignment with the alignment axis and close to the bend former, the mandrel being receivable longitudinally Within a workpiece being bent.

4. In bending apparatus suitable for the bending of workpieces of the kind referred to and which includes bend parts comprising a bend former and at least one coating part to clamp a workpiece for bending transverse to an alignment axis, and which includes actuating means for displacing at least one of the bend parts to bend the workpiece, the actuating means including an electrical control circuit in which there is provided a limit switch and a stop relatively displaceable to each other by connecting means displaceable in proportion to the displacement of the bend part bending the workpiece during a bending operation: locating means for locating a workpiece co-axially with and relative to the alignment axis by locating one end of the workpiece both in axial distance from the bend former and in its rotational disposition about the alignment axis, and comprising a shaft disposed longitudinally and having its axis parallel to the alignment axis; axially spaced transversely disposed arms fast with and circumferentially spaced about the axis of the shaft, the axial spacing between the various arms corresponding to the various pitches between bends to be formed in the workpiece; engaging means on each transverse arm and mounted to be adjustable in position in the arm about an axis parallel to the shaft axis, for the polar location of a workpiece about the alignment axis to determine the angle between the planes of the bends to be formed in a workpiece; a plurality of stops corresponding each to a transverse arm to determine the degree of bend corresponding to the transverse arm; a carrier member carrying the stops in space relation; and inter-connecting drive means drivingly connecting the shaft and the carrier for positioning the carrier to bring a stop corresponding to a particular arm in register with the limit switch when the axis of the engaging means of that arm is coaxial with the alignment axis.

5. The structure of claim 4 in which the carrier com prises a spider mounted to rotate about an axis, the stops being circumferentially spaced about the spider rotational axis at varying axial positions corresponding to the degree of bends required and corresponding to the arms.

6. The structure of claim 4 and which includes indexing means whereby the positioning sequence of transverse arms whose engaging means are required to come in coaxial alignment with the alignment axis can be determined.

7. The structure of claim 6, in which the indexing means comprises an index plate connected to the shaft at a position away from the bend former, the plate having circumferentially spaced notches about the shaft axis, each notch corresponding to an arm; a dog arranged to enact with a notch to locate the index plate and hence the shaft and arms in a position corresponding to the notch; bias means arranged to urge the dog towards engagement with the notches; a biassed catch arranged to retain the dog out of engagement against the action of the bias means; a plurality of removable shoulders fast with the index plate and each corresponding to a notch and spaced circumferentially about the axis of the shaft, the positioning of the shoulders about the shaft axis corresponding to that of the notches, each shoulder being adapted to release the catch when its notch registers with the dog; shaft drive means to rotate the shaft about its axis; an index switch for de-energizing the shaft drive means and mounted in proximity to the dog such that the index switch is in the de-energizing position when the dog is in the engaged position with a notch and in the energizing position when out of engagement; whereby when a notch is in register with the dog the axis of the engaging means of the arm corresponding to that notch is coaxial with the alignment axis, and whereby any arm may be omitted from operation by removing its shoulder from the index plate and whereby a shoulder cor- 1b responding to a particular arm when the index plate rotates is adapted to release the catch thereby freeing the dog which is then urged by its bias means into the notch corresponding to that shoulder and arm, and whereby displacement of the dog to engage the notch operates the index switch to tie-energize the shaft drive means.

8. The structure of claim 7 in which the shaft drive means includes a slip clutch arrangement for taking up overrun of the shaft drive means when the dog engages with a notch.

9. The structure of claim 7 and adapted to locate a tubular workpiece and in which the engaging means comprises a plug to enter the end of the tube; a transverse projection connected to the plug and projecting radially beyond it, and adapted to engage with a notch provided in the end of the tube; adjusting means for adjusting rotationally the position of the plug and the projection about the plug axis.

10. Bending apparatus suitable for the bending of workpieces of the kind refer-red to and which includes a bend block of segmental shape and a pair of biassed wing dies mounted to pivot about a pair of longitudinally spaced transverse axes one on either side of the bend block, the bias being arranged to urge the Wing dies towards the bend block for clamping a workpiece against the bend block for bending transverse to an alignment axis, actuating means for displacing the bend block against the action of the bias means of the wing dies and transversely to the alignment axis, the actuating means comprising an electrical control circuit in which there is provided a limit switch and a stop relatively displacea ble to each other by connecting means displaces-hie in proportion to the displacement of the :bend block during a bending operation; and locating means for locating a workpiece coaxially with and relative to the alignment axis by locating one end of the workpiece both in axial distance from the bend former and in its rotational disposition about the alignment axis, and comprising a shaft disposed longitudinally and having its axis parallel to the alignment axis; axially spaced transversely disposed arms fast with and circumferential-1y spaced about the axis of the shaft, the axial spacing between the various arm-s corresponding to the various pitches between bends to be formed in the workpiece; en gaging means on each transverse arm and mounted to be adjustable in position in the arm about an axis parallel to the shaft axis for the polar location of the workpiece about the alignment axis to determine the angle between the planes of the bends to be formed in the workpiece; a plurality of stops corresponding each to a transverse arm to determine the degree of bend corresponding to the transverse arm; a carrier member carrying the stops in spaced relation; interconnecting drive means drivingly connecting the shaft and the carrier for positioning the carrier to bring a stop corresponding to a particular arm in register with the limit switch when the axis of the engaging means of that arm is co-axial with the alignment axis; indexing means whereby the positioning sequence of transverse arms whose engaging means are required to come into co-axial alignment with the alignment axis can be determined, and comprising:

(a) an index plate connected to the shaft at a position away from the bend former, the plate having circumferentially spaced notches about the shaft axis, each notch corresponding to an arm;

(1)) a dog arranged to co-act with a notch to locate the index plate and hence the shaft and arms in position corresponding to the notch;

(c) bias means arranged to urge the dog towards engagement with the notches.

(d) a biassed catch arranged to retain the dog out of engagement against the action of the bias means;

(e) a plurality of removable shoulders fast with the ind-ex plate and each corresponding to a notch and spaced circumferentially about the axis of the shaft, the positioning of the shoulders about the shaft axis corresponding to that of the notches, each shoulder being adapted to release the catch when its notch registers with the dog;

(f) shaft drive means to rotate the shaft about its axis;

g) an index switch for de-energizing the shaft drive means and mounted in proximity to the dog such that the index switch is in the de-energizing position when the dog is in the engaged position with a notch and in the energizing position when out of engagement; whereby when a notch is in register with the dog, the axis of the engaging means of the arm cor-responding to that notch is co-axial with the alignment axis, and whereby any arm may be omitted from operation by removing its shoulder from the index plate and whereby a shoulder corresponding to a particular arm when the index plate rotates is adapted to release the catch, thereby freeing the dog which is then urged by its bias means into the notch corresponding to that shoulder and arm, and whereby displacement of the dog to engage the notch operates the index switch to de-energize the shaft drive means.

11. .The structure of claim in which the shaft drive means of the locating means includes a slip clutch arrangement for taking up overrun of the shaft drive means when the dog engages with a notch.

1-2. Bending apparatus suitable for the bending of tubes, and which includes a frame part, bending parts comp-rising a bend block of segmental shape, and a pair of co-acting biassed wing dies mounted to pivot about a pair of longitudinally spaced parallel axes, one on either side of the bend block and transverse to an alignment axis, whereby a tube may be clamped between the bend block and the wing dies for bending transversely to the alignment axis; actuating means for displacing the bend block and comprising a pressure head having slack between it and the frame part, an electrical control circuit in which there is provided a limit switch for reversing the actuating means, connecting means interconnecting the limit switch and at least one wing die for displacing the limit switch in proportion to the displacement of the said wing die and hence of the bend block during a bending operation; and locating means for locating a tube co-axially with and relative to the alignment axis, by locating one end of the tube both in axial distance from the bend former and in its polar disposition about the alignment axis, and comprising:

(a) a shaft disposed longitudinally and having its axis parallel to the alignment axis;

(12) axially spaced transversely disposed arms fast with the shaft and circumferentially spaced about the axis of the shaft, the axial spacing between the various arms corresponding to the various pitches between the bends to be formed in the tube;

(0) engaging means on each transverse arm and mounted to be adjustable in position in the arm about an axis parallel to the shaft axis for the polar location of a tube about the alignment axis to determine the angle between the planes of the bends to be formed in the tube, and comprising:

(i) a plug to enter the end of the tube;

(ii) a transverse projection connected to the plug and projecting radially beyond it, and adapted to engage with a notch provided in the end of the tube; and

(iii) adjusting means for adjusting rotationally in the arm, the position of the plug and the projection about the plug axis;

(d) a plurality of stops corresponding each to a transverse arm to determine the degree of bend corresponding to the transverse arm;

(e) a carrier member carrying the stops in spaced relation;

(f) interconnecting drive means drivingly connecting the shaft and the carrier for positioning the carrier to bring a stop corresponding to a particular arm, in

CPI

register with the limit switch when the axis of the engaging means of that arm is coaxial with the alignment axis, the spacing between the limit switch and a registering stop being proportional to the degree of bend corresponding to the stop and its corresponding transverse arm; whereby displacement of the limit switch during a bending operation will cause it to abut against the stop with which it is in register, thereby causing the limit switch to operate to reverse the actuating means;

(g) indexing means whereby the positioning sequence of transverse arms whose engaging means are required to come into co-axial alignment with the alignment, can be determined, and comprising;

(i) an index plate connected to the shaft at a position away from the bend former, the plate having circumferentially spaced notches about the shaft axis, each notch corresponding to an arm;

(ii) a dog arranged to co-act with a notch to locate the index plate and hence the shaft and arms in a position corresponding to the notch;

(iii) bias means arranged to urge the dog towards engagement with the notches;

(iv) a biased catch arranged to retain the dog out of engagement against the action of the bias means;

(v) a plurality of removable shoulders fast with the index plate, and each corresponding to a notch and spaced circumferentially about the axis of the shaft, the positioning of the shoulders about the shaft axis corresponding to that of the notches, each shoulder being adapted to release the catch when each notch registers with the dog;

(vi) shaft drive means to rotate the shaft about its axis; and

(vii) an index switch for de-energizing the shaft drive means and mounted in proximity to the dog, such that the index switch is in the deenergizing position when the dog is in the engaged position with a notch, and in the energizing position when out of engagement; whereby when a notch is in register with a dog, the axis of the engaging means of the arm corresponding to that notch, is co-axial with the alignment axis, and whereby any arm may be omitted from operation by removing its shoulder from the index 'plate, and whereby a shoulder corresponding to a particular arm when the index plate rotates, is adapted to release the catch, thereby freeing the dog which is then urged by its bias means into the notch corresponding to the shoulder and the arm, and whereby displacement of the dog to engage the notch, operates the index switch to deenergize the shaft drive means;

(Iz)bt1iearing means supporting the shaft axially displace- (i) bias means urging the shaft axially towards a forward position;

(i) electrically controllable displacing means for displacing the shaft against the bias means into a retracted position;

(k) a lever system connecting the said displacing means to the dog;

(I) an energizing circuit for the shaft drive means; and

(m) a head switch in series with the energizing circuit, and with the index switch, and located to be operable by displacement of the pressure head and the frame par-t relative to each other in taking up the slack when gripping a workpiece to be bent; whereby energizing of the energizing circuit by operation of the headswitch when the slack is taken up, energizes the displacing means to displace the shaft into its retracted position and the dog via the lever system into its disengaged position; and whereby the tube is mere- 1y gripped between the bend former and wing dies while the plug is retract-ed from the tube end to free the end of the tube and permit deflection of the tube end during the bending operation, and whereby the index switch is closed by withdrawal of the dog from a notch to cook the energizing circuit for the shaft drive means, whereby indexing for the next bending operation takes place after operation of the head switch by the pressure head on its return stroke to energize the energizing circuit of the shaft drive means.

13. Bending apparatus according to claim 12 in which the shaft is provided with longitudinal graduations having its datum point in line with the intersection of the centre line of the bend block and the alignment axis and whereby the arms of the shaft may be positioned longitudinally in position on the shaft in correspondence with the longitudinal spacing between bends in the workpiece.

14. Bending apparatus according to claim 12 in which the limit switch is mounted upon a shoe linearly displaceable towards a stop, guide means for guiding the shoe linearly, shoe bias means urging the shoe away from the stop, a flexible tensile member having one end connected to the shoe and the other end connected to the face of a cam provided, the cam being fast with one of the wing dies, and being arcuately displaceable therewith; whereby arcuate displacement of the cam causes linear displacement of the shoe towards a stop against the action of the shoe bias means, the cam face having a profile such that the linear displacement of the shoe is directly proportional to the arcuate displacement of the cam face about the axis of the shaft.

15. In bending apparatus suitable for the bending of a tubular workpiece and which includes bend parts comprising a bend former and at least one coacting clamp part to clamp a workpiece for bending transverse to an alignment axis, and actuating means for displacing at least one of the bend parts to bend the workpiece: locating means for locating a tubular workpiece coaxially and relative to the alignment axis by locating one end of the workpiece both in axial distance from the bend former and in its polar disposition about the alignment axis, and comprising a shaft disposed longitudinally and having its axis parallel to the alignment axis; axially spaced transversely disposed arms fast with and circumferentially spaced about the axis of the shaft, the axial spacing between the various arms corresponding to the various pitches between bends to be formed in a workpiece; and engaging means on each transverse arm and comprising a plug to enter the end of the tubular workpiece and being mounted in a socket in the arm to be adjustable in position in the arm about an axis parallel to the shaft axis, a transverse projection connected to the plug and projecting radially beyond it, and adapted to engage with a notch provided in the end of the tube, for the polar location of the tubular workpiece about the alignment axis to determine the angle between the planes of the bends to be formed in the workpiece.

References Cited by the Examiner UNITED STATES PATENTS 1,719,366 7/29 Grifiiths et a1 83-393 2,349,525 5/44 St. Clair.

2,543,759 3/51 Cannon et al 15321 2,669,276 2/54 Humphrey.

2,779,382 1/57 Anello 15348 2,797,724 7/ 57 Walldow 153-21 2,998,838 9/61 Byrd 15340 FOREIGN PATENTS 155,378 2/54 Australia.

CHARLES W. LANHAM, Primary Examiner. 

1. IN BENDING APPARATUS SUITABLE FOR THE BENDING OF WORKPIECES OF THE KIND REFERRED TO AND WHICH INCLUDES BEND PARTS COMPRISING A BEND FORMER AND AT LEAST ONE COACTING PART TO CLAMP A WORKPIECE FOR BENDING TRANSVERSE TO AN ALIGNMENT AXIS, AND ACTUATING MEANS FOR DISPLACING AT LEAST ONE OF THE BEND PARTS TO BEND THE WORKPIECE: LOCATING MEANS FOR LOCATING A WORKPIECE COAXIALLY WITH AND RELATIVE TO THE ALIGNMENT AXIS BY LOCATING ONE END OF THE WORKPIECE BOTH IN AXIAL DISTANCE FROM THE BEND FORMER AND IN ITS ROTATIONAL DISPOSITION ABOUT THE ALIGNMENT AXIS, AND COMPRISING A SHAFT DISPOSED LONGITUDINALLY AND HAVING ITS AXIS PARALLEL TO THE ALIGNMENT AXIS; AXIALLY SPACED TRANSVERSELY DISPOSED ARMS FAST WITH AND CIRCUMFERENTIALLY SPACED ABOUT THE AXIS OF THE SHAFT, THE AXIAL SPACING BETWEEN THE VARIOUS ARMS CORRESPONDING TO THE VARIOUS PITCHES BETWEEN BENDS TO BE CORMED IN THE WORKPIECE; AND ENGAGING MEANS ON EACH TRANSVERSE ARM AND MOUNTED TO BE ADJUSTABLE IN POSITION IN THE ARM ABOUT AN AXIS PARALLEL TO THE SHAFT AXIS, FOR THE POLAR LOCATION OF A WORKPIECE ABOUT THE ALIGNMENT AXIS TO DETERMINE THE ANGLE BETWEEN THE PLANES OF THE BENDS TO BE FORMED IN THE WORKPIECE. 